[vtkusers] vtkDICOMImageReader origin

[DVigneault]

All--

I'm having a problem where vtkDICOMImageReader is (incorrectly) giving an
origin of zero.  I have two programs (code below) to read in the image and
print out the dimension/spacing/origin--the first with ITK, the second with
VTK.  The two programs give the same dimension and spacing, but the ITK
program gives a nonzero origin and the VTK program gives a zero origin. The
two programs are reading the same dataset.  Am I misusing the
vtkDICOMImageReader somehow?  Has anyone come across this before?

Best, and thanks,

--Davis

//
// VTK
//

#include "vtkSmartPointer.h"
#include "vtkDICOMImageReader.h"
#include "vtkImageData.h"

int main(int argc, char ** argv)
{

  vtkSmartPointer< vtkDICOMImageReader > reader =
    vtkSmartPointer< vtkDICOMImageReader >::New();
  reader->SetDirectoryName("../../data/ct_heart");
  reader->Update();

  vtkSmartPointer<vtkImageData> data =
    vtkSmartPointer<vtkImageData>::New();
  data = reader->GetOutput();

  int dims[3];
  data->GetDimensions(dims);
  
  double spacing[3];
  data->GetSpacing(spacing);

  double origin[3];
  data->GetOrigin(origin);

  std::cout << "Dimensions: [" << dims[0] << ", " << dims[1] << ", " <<
dims[2] << "]" << std::endl;
  std::cout << "Spacing: [" << spacing[0] << ", " << spacing[1] << ", " <<
spacing[2] << "]" << std::endl;
  std::cout << "Origin: [" << origin[0] << ", " << origin[1] << ", " <<
origin[2] << "]" << std::endl;

// Output:
// Dimensions: [512, 512, 120]
// Spacing: [0.332, 0.332, 1]
// Origin: [0, 0, 0]


  return EXIT_SUCCESS;
}

//
// ITK
//

#include "itkImage.h"
#include "itkGDCMImageIO.h"
#include "itkGDCMSeriesFileNames.h"
#include "itkImageSeriesReader.h"

typedef itk::Image< short, 3 >   TInImage;
typedef itk::GDCMImageIO                              TImageIO;
typedef itk::GDCMSeriesFileNames                      TImageNames;
typedef itk::ImageSeriesReader< TInImage >            TImageReader;

int main( int argc, char* argv[] )
{

  TImageIO::Pointer dicomIO = TImageIO::New();

  TImageNames::Pointer names = TImageNames::New();
  names->SetInputDirectory( "../../data/ct_heart" );
  
  TImageReader::Pointer imageReader = TImageReader::New();
  imageReader->SetImageIO( dicomIO );
  imageReader->SetFileNames( names->GetInputFileNames() );
  imageReader->Update();

  std::cout << "Dimensions: " <<
imageReader->GetOutput()->GetLargestPossibleRegion().GetSize() << std::endl;
  std::cout << "Spacing: " << imageReader->GetOutput()->GetSpacing() <<
std::endl;
  std::cout << "Origin: " << imageReader->GetOutput()->GetOrigin() <<
std::endl;

// Output:
// Dimensions: [512, 512, 120]
// Spacing: [0.332, 0.332, 1]
// Origin: [-71.084, -93.584, 1562.5]

  return EXIT_SUCCESS;

}




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